A debilitating and poorly understood health condition which causes the heart rate to accelerate rapidly upon standing up predominantly affects young, well educated women, new evidence has shown.

Researchers who set out to understand more about the rare postural tachycardia syndrome (PoTS) discovered that sufferers had an average age between 30 and 33, and were more likely to be educated to degree or postgraduate degree level.

The reasons for the association remain mysterious.

PoTS is believed to affect around one in 558 people, based on figures from the USA, but many doctors are still unaware of its existence. It is often misdiagnosed, or attributed to an associated condition such as anxiety, panic disorder, or chronic fatigue.

The new study, published in the online journal BMJ Open today, assessed 84 members of the national support group PoTS UK, and 52 patients diagnosed at an NHS clinic in Newcastle.

Many had been forced to change jobs or give up work by the condition, which causes fatigue and makes many basic, everyday tasks exhausting and difficult.

Researchers said that increasing awareness of the condition would be crucial to improving diagnosis rates and understanding.